Gripping his weapon with his right hand, Dempsey took his left away from the rifle’s magazine, slowly moved it past his own back and tapped Gallo’s hip. The Italian – his own eyes still fixed on the apartment’s main door – responded by placing a single flash-bang into Dempsey’s outstretched hand.

It was their only cover for the breach that was to come. Or at least for the breach they expected to come.

There is a difference between being deafened and being unable to ‘hear’. The key is to recognise the vibrations elsewhere. To detect that feeling that would ordinarily be called ‘sound’.

It was this vibration that Dempsey absorbed, just as he lifted the flash-bang towards his right hand. The sensation of movement, emanating up through his boots. Too light to be a footstep. Almost too light, even, to be noticed.

Almost.

The small, brown object that rolled into the doorway was as rudimentary a hand grenade as Dempsey had ever seen. Barely larger than a squash ball and almost featureless, the antiquated fragmentation grenade’s blast zone would be small, but it was still perfectly capable of tearing Dempsey and Gallo to pieces.

Dempsey stopped the deadly ball with his left boot, scooped it up from the floor and sent it arching back from where it had come. In the next instant he unpinned Gallo’s flash-band and threw it in the same direction.

‘COVER!’

Dempsey grabbed Gallo hard by the shoulder as he shouted, using his full strength to pull the Italian to the floor and behind whatever protection the interior wall could provide.

It was not a moment too soon.

The sound of the first bang would have been deafening if either man could still hear, while its flash – fifty per cent of its disorientating arsenal – was harmless on this side of the partition. Even alone, the weapon would have been effective.

But it was not alone.

The fragmentation grenade exploded almost simultaneously. As soon as it hit the floor, Dempsey assumed. Its devastating effect made the first device seem like a child’s toy.

Large fragments of the grenade pierced the drywall that divided the main room from the rest of the apartment. None struck Dempsey or Gallo, thanks to their position on the floor. Had either man been standing, the result would have been very different.

‘LET’S GO!’ Dempsey yelled. If anyone was still alive through the doorway, they could not be given time to recover.

Both men were on their feet in an instant, with Dempsey first through the doorway and Gallo a step behind him.

The sight that met them was like a snapshot of hell. Whatever damage the grenade had done through the wall was multiplied ten times over on the partition’s other side.

It took a literal headcount for Dempsey to determine that a further four targets had been eliminated in the explosion. Two in the tight corridor off the main room – presumably the original source of the grenade – and two on the threshold of the first bedroom.