My guess is you've got the APs in the corridors? Is that right?
If it is, it's likely the APs "hear" each other quite well, as they've line of sight to one another. As a result, they may well reduce power (with consequences concerning coverage into rooms, which would require obstacle penetration).
Upp'ing your min power is one approach. I'd recommend you do some sample baseline tests. I.e. go to one location, equal distance between APs, and move into a room off the corridor (to the furthest wall). Adjust the min power to suit, and repeat?
Of course, if that's not your AP layout this isn't good advice!!!