system
Given the following post, respond as if you're commenting on Reddit:
human
[ASoIaF/GoT] Could Barristan Selmy have succeeded in cutting his way through the Kingsguard?
gpt
Doubtful. 

Barristan Selmy is an incredible fighter but there is a few things to consider. 

1. It's 1v5. This might not be so bad if it's Selmy in full armour against a group of random peasants, but he's up against five capable fighters in full armour. Robert's Kingsguard were poor in comparison to Selmy's former brothers, but they're not pushovers. 

2. Selmy is about 63 at this point. Once again, he's an incredible fighter, but age doesn't discriminate. He's up against five men who are 20-30 years younger than him. 

3. Not only are there five other Kingsguard there, but there are also the Goldcloaks and Sandor Clegane present as well. Starting a fight against them all would be suicide. 

It's more of a boast brought on by the heat of the moment, and it's also him venting his frustration at the state of the Kingsguard. This is a man who served besides Arthur Dayne, Gerold Hightower, Oswell Whent, Jonothor Darry, and Lewyn Martell. He's basically seen the Kingsguard go from the best it could possibly be to rock bottom in the space of fifteen years.