Endless air in the brake lines? '01 Camry
 

Brakes are very soft and unsafe so thought I'd start by bleeding them. Got a kit with a bottle you fill with brake fluid that hangs into the master cylinder and the bleeder hooks to air compressor....sure you've all seen these. Starting at rear passenger wheel I spent 15 minutes at PSI of about 90 and all I get are dribbles of brake fluid but mostly just air (like 80% air?). Drained the inverted bottle by a bit more than half. Checked the master cylinder, kept it full etc.
How long until this air is drained? Or is the air coming in from somewhere else? Seems like tons of air. I have no brake fluid leaks and the connection to the nipple is tight and the nipple is just cracked open. I can watch the fluid level drop in the master cylinder so it seems to be moving quickly to the "exit" so to speak.
In the past I had a friend pump the brakes while I cracked and closed the nipple etc. Result seemed good, full of brake fluid after some bubbles worked through. But this was front driver wheel, not sure if that matters.
Also it seems the air hose connection is not the tightest, lots of hissing so maybe 90psi is not what’s at play. But the what little fluid there is does zip right through into the cup.
Worse case: lets say I messed up and air did get sucked into the master cylinder "system". Will this simply suck through with no issues as long as I make sure fluid stays topped off or have I damaged it somehow?
Thanks everyone!