How did Ibarra survived the pursuit of the civil guards? Chapter 60-61

In Chapter 61, Ibarra and Elias are in a boat conversing when a group of Civil Guard members on a boat find them and begin chasing them. Ibarra ducks and Elías tries to out-row the Civil Guard members, but it’s clear his boat isn’t fast enough. Elías dives off the boat, pretending to be Ibarra, while Ibarra plans to row to shore. The plan works, and the Civil Guard members pursue Elías, shooting at him. Eventually, they are convinced he is dead, though they don’t find his body.