Also, makes sense why Loki callled Shanks a coward back then when he was rage baiting Luffy.
Shanks wanted to play smart and not crash directly with the WG, while Loki wanted to crash directly with the WG face-to-face.
Shanks actually saved Loki's life by imprisoning him, cause he would have no chance against WG forces,, to say even a full powered Imu.