Based on your sketch, I get the following calculation:
The whole corridor is 30m long as your prior statement. The drones began to attack when we were about 10m in, Kynos went to stealth further and the guard began to fire. Since one guard had a definite Ini advantage, I assume that Kynos didn't get more than 5m, so about half way down the corridor.
Targeting the far wall, that means, Kynos faces the blast into his direction as well as the door of the operations room (assuming a bunker door with armor greater 18 so it isn't affected by the blast).
That means there is a wave of 16+16=32 DV coming at Kynos, losing 2 DV per meter. At 15m that leaves 2 DV.
(The explosion vectors to the sides are irrelevant since those are reflected at 180° back and forth)
Soak Explosion:
29d6t5 7Kynos could be up to 18m in without suffering damage.
Now for the guys behind the barricade (I assume the barricade did not in fact slow down the explosion in Kynos direction otherwise it would be even less damage in his direction)
I realize your sketch is likely not to scale, but the proportions indicate a 1 to 5 ratio from wide to length, leaving the corridor at about 6 m wide.
Now it's getting interesting: 16 DV travelling 3m to each side will lose 6 DV and reflect with 10DV reaching the center with 4 DV and dissipating before it reaches the other side. But there are two walls and the ceiling (I'll leave the floor out since that should be included in the base damage) which I assume is 3m high for conveniens so the center gets 16+4+4+4+16 from the door behind, creating a pressure point of 44 DV.
Whatever was there, now it's a fine paste.