falling, collapsing / (to meet) unexpectedly / (to halt) suddenly, abruptly

stairs, staircase / ladder, a series of steps to advancement to be followed in order

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

落ちる: to fall

to fall / (computing) to go down (as when a computer or application becomes unresponsive) / (electrical engineering, of a circuit breaker) to trip / (informal) to fail an examination

stairs used in emergencies

spiral staircase

(colloquial) current boyfriend