Depends on what you consider "major issue". If you have living people underground and a massive steel door that is the only entrance, the situation is tricky. Y

Depends on what you consider "major issue". If you have living people underground and a massive steel door that is the only entrance, the situation is tricky. You cannot use too many explosives, because the building could collapse on you and them. Neither you want to create some massive shockwave inside. But at the same time, you don't want to spend days slowly disassembling the system. They are hungry and possibly thirsty down there.