does anyone know how opening the door works on stars lol? i had this hand and it really surprised me

PokerStars Hand #199803698985: Tournament #2596921076, $3.19+$0.31 USD Hold'em No Limit - Level VI (80/160) - 2019/04/28 15:09:54 MT [2019/04/28 17:09:54 ET]
Table '2596921076 3' 9-max Seat #9 is the button
Seat 1: (285 in chips)
Seat 2: (1468 in chips)
Seat 3: (4615 in chips)
Seat 5: (2804 in chips)
Seat 6: (3180 in chips)
Seat 7: (1877 in chips)
Seat 9: (4904 in chips)

*** HOLE CARDS ***

folds
folds
V1 calls 160
folds
calls 160
SB raises 105 to 265 and is all-in
BB calls 105
V1 raises 215 to 480

SB shoves for less than a big blind more and then the door is open??? what someone explain please